About Virtual Machine. How to Access Hardware Devices in VM
Virtual Machine is a completely separate individual operating system installation on your usual operating system. It is implemented by software emulation and hardware virtualization.
Virtual machine is a software implementation of a physical machine - computer - that works and executes analogically to it. Virtual machines are divided in two categories based on their use and correspondence to real machine: system virtual machines and process virtual machines. First category provides a complete system platform that executes complete operating system, second one will run a single program.
Frequently multiple virtual machines with their own OS's are used in server consolidation, where different services are run in separate virtual environments, but on the same physical machine.
The main advantages of virtual machines:
- Multiple OS environments can exist simultaneously on the same machine, isolated from each other;
- Virtual machine can offer an instruction set architecture that differs from real computer's;
- Easy maintenance, application provisioning, availability and convenient recovery.
The main disadvantages:
- When multiple virtual machines are simultaneously running on a host computer, each virtual machine may introduce an unstable performance, which depends on the workload on the system by other running virtual machines;
- Virtual machine is not that efficient as a real one when accessing the hardware.
Virtualization brings you a number of advantages – centralizing network management, reducing dependency on additional hardware and software, etc. But as it is always the case, it has certain shortcomings too.
There are a lot of cases when the virtualization software struggles to provide full and reliable forwarding of USB and serial devices to the virtual environment (e.g. VMWare, ESX, Microsoft Hyper-V). Or the appliance can be accessed from the virtual machine but it may not function properly. How to deal with that situation?
When accessing a USB or serial device from a virtual machine becomes a problem, USB Network Gate and Serial over Ethernet Connector come to rescue. Thanks to their port redirection technology, the dedicated programs allow forwarding USB and serial peripherals over network to virtual environments (VMWare, ESX, Microsoft Hyper-V, etc.). With the software you will be able to access a USB or serial device from your guest OS, even if the device is not plugged into the host OS but connected to a remote PC.